Bosh construction for metallurgical furnaces

ABSTRACT

A metallurgical furnace bosh construction has a protective liner over the heat conductive lining along the interior surface of the outer jacket, the protective liner forming an adhesion surface for slag formed as a by-product of the metallurgical reaction within the furnace, the liner being positioned substantially outside the tuyere raceway initially and being covered by a temporary layer of refractory material.

United States Patent 1 [111 3,810,610 Berczynski [45] M 14, 1974 [54] BOSH CONSTRUCTION FOR 3,379,427 4/1968 Zherebin et a]. 266/43 x METALLURGICAL FURNACES 1,517,820 12/1924 Bong 266/43 3,552,732 1/1971 Rice 266/43 [75] Inventor: Frank Berczynski, Wflhamsvllle. 3,148,238 9/1964 Willenbrock, Jr. 432/248 x [73] Assignee: Andco Incorporated, Buffalo. N.Y. Pflmary Lake Assistant Examiner-James F. Coan Filed: l 11, 1972 Anorney, Agent, or Firm-Christel & Bean [2]] Appl. No.: 287,725

[57] ABSTRACT [52] US. Cl. 266/43, 432/247 A melanul'gical furnace bosh construction has a P 51 Int. Cl C21b 7/06, c21 5/44 motive liner Over the heat conductive lining along the [58] Field f Search 2 43 2 432 2 2 interior surface of the outer jacket, the protective 432 252 liner forming an adhesion surface for slag formed as a by-product of the metallurgical reaction within the [5-6] References Cited furnace, the liner being positioned substantially out- UNITED STATES PATENTS side the tuyere raceway initially and being covered by a temporary layer of refractory material. 2,567,007 9/l95l Brassert et al. 266/43 X 3,652,070 3/1972 Sagara l 266/43 X 8 Claims, 2 Drawing Figures '2 SZIIIIIIIA 2 3 gri l/III! i -.'I' 7 irlllllllm Q VII/11am 1w" El 1 BOSH CONSTRUCTION FOR METALLURGICAL FURNACES BACKGROUND OF THE INVENTION Efforts to increase the length of furnace campaigns have been hampered by premature bosh failure. Erosion, particularly in the lower portion of the bosh, frequently results in one or more breakouts, often when the furnace campaign is far short of its goal. This poses a safety hazard to operating personnel, and reduces furnace efficiency.

While repair can be effected externally, by application of additional lining and jacket material over the region of the breakout, the problems of safety and campaign interruption remain.

SUMMARY OF THE INVENTION The primary object of this invention is to provide a bosh construction and arrangement which will avoid such premature failure and thereby contribute to the goals of greater safety and longer furnace campaigns.

It is another object of this invention to provide a bosh construction for metallurgical furnaces which is relatively simple, inexpensive and easy to install, and wherein the integrity of the heat conducting lining is preserved in a manner avoiding premature bosh failure.

The bosh construction of this invention is characterized by the provision of a protective liner for the heat conducting lining which also provides an adhesion surface for the formation of slag from the by-products of the metallurgical reaction, the protective liner being positioned substantially outside the tuyere raceways thereby to avoid the abrasive effect thereof.

The foregoing and other objects, advantages and characterizing features of this invention will become clearly apparent from the ensuing detailed description of an illustrative embodiment thereof, reference being made to the accompanying drawings wherein like reference numerals denote like parts throughout.

DESCRIPTION OF THE DRAWING FIGURES FIG. 1 is a fragmentary vertical sectional view of a construction of this invention, prior to blow-in; and

FIG. 2 is a similar view thereof after blow-in.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT Referring now in detail to the illustrative embodiment depicted in the accompanying drawings there is shown in FIG. 1 a representative blast furnace incorporating a bosh construction of this invention, showing a portion of the lower in-wall section with itsjacket 1, refractory 2 and copper cooling plates 3, the in-wall section resting on a mantle 4 supported by columns 5, all in a manner known in the art.

The bosh section has an outer jacket 6 with its upper end flange 7 engaging the mantle flange 8. Adjacent the lower end of bosh jacket 6 there is positioned a collector 9 for cooling water applied to the exterior surface of jacket 6 as by spray nozzles or a weir arrangement such as disclosed in U.S. Pat. No. 3,6l2,50l, it being understood that any suitable cooling arrangement can be used and is intended to be broadly indicated by the showing of collector 9.

At the lower end of jacket 6 there is provided an expansion joint 10 including a flange 11 at the upper end of the tuyere breast 12. Any suitable number of tuyeres will be provided, one being shown by way of example only and represented by tuyere cooler 13 and tuyere 14 having, for reference purposes a nose 15.

The interior surface of bosh jacket 6, and also of mantle flange 8 is lined with bricks or blocks of carbon or other highly heat conductive material such as fuse cast refractories or graphite, as shown at 16, which lining also is provided along the interior surface of tuyere breast 12, as shown at 17.

The purpose of lining 16 is to conduct heat from the furnace to the jacket 6 where it is dissipated by external cooling of the jacket which therefore functions'both as a heat conductor and as an enclosing shell for the furnace. The integrity of the carbon lining 16 is a very important factor in prolonging furnace life, and lining 16 is subject to attack, with resulting loss of integrity as a result of the metallurgical reaction within the furnace. Where lining 16 is of carbon, which often is the case, oxygen present in the furnace combines with the carbon lining consuming it. Also, the abrasive action of materials within the furance, during the metallurgical reaction, is physically destructive of the lining surface.

It is a particular feature of my invention that lining 16 is protected from attack, both chemical and physical, by a protective'liner 18 which covers lining 16 from the lower end of jacket 6 upwardly, beyond jacket flange 7 and mantle flange 8 to a liner flange 19 which is welded to the plate of mantle 4. Thus, the carbon lining of both mantle flange 8 and jacket 6 is completely covered by protective liner 18 which is attached at its upper end and permitted to float, free of physical attachment, at its lower end thereby accommodating relative expansion movement of liner 18.

Liner 18 is of a material capable of providing a physical barrier between lining l6 and the interior of the furnace, thereby protecting lining 16 against destructive contact with the burden material and the slag byproduct of the metallurgical reaction. It is of a material which is impervious to the passage of oxygen, or substantially so, thereby protecting the lining against chemcial attack. In addition, it is of a material which provides a good adhesion surface for the slag, which is essentially silicon carbide, formed as a by-product of the metallurgical reaction. An example of a suitable material is carbon steel, which can be applied in plate form and which has a relatively porous surface for the adhesion of slag. Other ferrous materials, and even non-ferrous materials capable of subsisting in the metallurgical furnace environment and possessing the necessary characteristics, can be used although it is believed that ferrous materials will be found most practical.

While the illustrated arrangement, wherein the liner 18 is fixed at its upper end has the advantage of maintaining a substantialy gas tight arrangement except at its lower end where the lining is less subject to oxygen attack, it will be appreciated that liner 18 could be fixed at its lower end and permitted to expand through a floating expansion connection at its upper end. The inner face of carbon lining 16 is beveled or inclined, at

an angle conforming closely to the angle of inclination ceous paste, whereby lining 16 and liner 18 fit snugly one against the other, for uniform heat conduction between liner 18 and lining 16 across the face of the latter.

To complete the initial installation, a layer of refractory material 20 is positioned over liner 18. Unlike lining 16, the brick comprising refractory layer 20 need not be shaped to conform to liner l8 and can simply be laid up against liner 18 in the manner shown.

Inner refractory layer 20 is a temporary layer offering initial protection to the liner 18 during the furnace blow in. As the layer 20 is consumed, it is replaced by slag formed as a by-product of the metallurgical reaction within the furnace and which adheres to the inner surface of liner l8 and forms a protective slag lining thereover, as shown at 21 in H6. 2. it will be noted that the carbon lining 17 for tuyere breast l8is protected in the area above the tuyere by a continuation 22 of slag layer 21. Thus during blow-in and thereafter as the metallurgical reaction progresses, heat conductive lining 16 is shielded by liner 18 which protects it against oxygen attack and against physical attack, thereby maintaining and preserving the integrity of lining 18. Since lining 16 is protected, it need be no thicker than is required for its heat conductive function. Liner 18 itself is protected, initially by the refractory layer 20 and thereafter by the slag layer 21 as shown in. FIG. 2. Expansion joint 10, ll permits relative movement of jacket 6, and the free lower end ofliner 18 permits relative expansion movement of the liner.

To better enable the laminated bosh construction of this invention to withstand the physical abrasive forces which are present during operation of the furnace I position the same so that liner 18 is substantially outside the raceway present at the nose of the tuyere. The rapidly moving materials present in a tuyere raceway produce an abrasive action which can be highly destructive, and by constructing the bosh to position liner 18 substantially outside of the raceway 1 am able to avoid the liner erosion which otherwise would occur. The raceway pattern and location will vary, depending upon a number of variables including blast conditions and coke quality. I have determined that the desired positioning of liner 18 relative to the raceway can be obtained by arranging it so as to be no less than about 4 feet from the vertical plane of the tuyere nose 5, at an elevation 4 feet above the horizontal center line of the nose.

From the foregoing it will be seen that my invention accomplishes its intended objects, by providing in a relatively simple and inexpensive construction a bosh wherein the heat conductive lining canbe of a thickness determined only by the heat conducting requirements, its integrity being maintained for a longer furnace campaign by the protective liner 18 which offers a good adhesion surface for slag formed during the metallurgical reaction and thereby obtains a protective slag coating as the reaction proceeds.

I claim:

1. In a metallurgical furnace having a tuyere, a bosh construction comprising an outer jacket, a lining of heat conducting material along the interior surface of said jacket, a protective liner over said heat conductive lining, and a layer of refractory material over said protective liner, said protective liner being of a material forming an adhesion surface for the by products of metallurgical reaction within said furnace, and said construction being arranged relative to the nose of said tuyere so as to position said protective liner substantially outside the raceway of said tuyere.

2. The combination of claim 1, wherein said protective liner is positioned substantially no less than 4 feet from the vertical plane of the nose of said tuyere at an elevation 4 feet above said tuyere nose.

3. The combination of claim 1, wherein said protective liner is of ferrous material.

4. The combination of claim 1, wherein the material of said heat conductive lining is carbon.

5. The combination of claim 1, together with means for cooling the exterior surface of said jacket.

6. The combination of claim 1, wherein said protective liner fits against said heat conductive lining in close fitting, surface conforming relation.

7. The combination of claim 1, wherein said liner is fixed adjacent one end thereof, its opposite end being free for expansion movement relative to the lining.

8. The method of constructing a metallurgical furnace bosh having an outer jacket and a lining of heat conductive material in proximity to a tuyere, which method comprises applying a protective liner over the heat conducting material, the liner being of a material providing an adhesion surface for the by products of metallurgical reaction within the furnace, orienting the jacket, lining and liner realtive to the tuyere nose so as to position the liner substantially outside the tuyere raceway, and installing a layer of refractory material over said liner.

* t ll 

1. In a metallurgical furnace having a tuyere, a bosh construction comprising an outer jacket, a lining of heat conducting material along the interior surface of said jacket, a protective liner over said heat conductive lining, and a layer of refractory material over said protective liner, said protective liner being of a material forming an adhesion surface for the by products of metallurgical reaction within said furnace, and said construction being arranged relative to the nose of said tuyere so as to position said protective liner substantially outside the raceway of said tuyere.
 2. The combination of claim 1, wherein said protective liner is positioned substantially no less than 4 feet from the vertical plane of the nose of said tuyere at an elevation 4 feet above said tuyere nose.
 3. The combination of claim 1, wherein said protective liner is of ferrous material.
 4. The combination of claim 1, wherein the material of said heat conductive lining is carbon.
 5. The combination of claim 1, together with means for cooling the exterior surface of said jacket.
 6. The combination of claim 1, wherein said protective liner fits against said heat conductive lining in close fitting, surface conforming relation.
 7. The combination of claim 1, wherein said liner is fixed adjacent one end thereof, its opposite end being free for expansion movement relative to the lining.
 8. The method of constructing a metallurgical furnace bosh having an oUter jacket and a lining of heat conductive material in proximity to a tuyere, which method comprises applying a protective liner over the heat conducting material, the liner being of a material providing an adhesion surface for the by products of metallurgical reaction within the furnace, orienting the jacket, lining and liner realtive to the tuyere nose so as to position the liner substantially outside the tuyere raceway, and installing a layer of refractory material over said liner. 